LONDON ­– Shrouded in dark shades after one of the most gruesome sports injuries you’ll ever see, five thoughts on Day Four from Wimbledon.

• With Serena Williams deep in the third set of pregnancy, there was no defending champ in the Wimbledon women’s draw. This was a rarity. This also marked a real opportunity for the rest of the field. Through two rounds, some of the most likely beneficiary are already heading home. Yesterday Petra Kvitova and Madison Keys both exited stage left. They’re both returning from injury, so the results were disappointing if not stinging. Not so with Thursday’s shocker. Karolina Pliskova—the favorite with the betting markets—fell to 87th-ranked Magdalena Rybarikova of Slovakia. The player with the best serve in the women’s game this side of Serena was broken five times. And she now has a losing record for her career at Wimbledon. Predict women’s draw at your own risk. Let the record reflect, Angelique Kerber—the top seed and a finalist in 2016—is still around.

• In their first round matches, Novak Djokovic and Roger Federer won in 40 minutes and 43 minutes, respectively, both benefitting—if that’s the right word—from the injury retirements of their opponents. On Thursday, each man got in a proper workout on Centre Court, but scarcely had to labor. Federer looked Federerian, getting better with each set and beating Dusan Lajovic 7-6, 6-3, 6-2. Djokovic absolutely blitzed Adam Pavlasek, 6-2, 6-2, 6-1 and caught a break when his next likely opponent, Juan Martin del Potro, was upset by Ernests Gulbis.

• Continuing a Latvia theme…..she didn’t play on Thursday but a hat tip to Jelena Ostapenko. The 20-year-old won the French Open last month and if this is was an unexpected result to most of us, it wasn’t to her. Complaining about a court assignment unworthy of a Grand Slam champion, Ostapenko has won her first two matches, making a statement given all that has befallen her over the last month. (“I’m not satisfied.”) She now plays the erratic (and arrears-ic) Camila Giorgi. With each match she wins, Ostapenko’s result in Paris looks a little less shocking.

• The ATP held an event this morning promoting the Next Gen ATP Finals, a first year event held November 7-11 in Milan featuring the best players 21-years-old and younger. Finding and promoting (that is, hyping) the next wave of talent is de rigeur in any sport. In men’s tennis it comes with an additional dimension given that four guys—all 30 years and older—have so thoroughly dominated the past decade. A tennis world without Federer, Nadal, Murray, and Djokovic, and is the accounting world without Deloitte, KPMG, PriceWaterhouse and Ernst & Young. Today two young guns faced off: Alexander Zverev beat Frances Tiafoe in straight sets, just as he did in Australia in January. Zverev is a different class of player right now; but you sense these two will continue battling for the next decade or so.

• There is little to say about the gruesome knee catastrophe Bethanie Mattek-Sands suffered—and we mean suffered—today. With the NSFW warning, there are video clips floating around. Injuries are, of course, part of all sports. But it’s hard to recall a scenario akin to what we saw today, a player screaming in agony as the opponent went into shock herself, other players cried, fans fainted and an ambulance motored to the side of the court.

One of the first rules of sports media: you don’t speculate on injuries. So we’ll await official word from the Mattek-Sands camp or the WTA. There are sports injuries that look minor and are, in fact, serious. (RGIII’s non-contact knee injury spring immediately to kind.) There are others that look gruesome and in fact less serious than first anticipated. You can only hope this falls into the latter category.